Apparatus for forming and lining pipes



Oct. 7, 1952 R. c. RIFENBURG 2,612,672

APPARATUS FOR FORMING AND 1.1mm; PIPES Filed May 31, 1951 5 Sheets-Sheetl INVEN TOR.

[sf-u. A 'k -AL ATTUKA/EKi RAY C.RIFEN suns.

Oct. 7, 1952. R. c. RIFENBURG 2,612,672

APPARATUS FOR FORMING AND LINING PIPES Filed May 51, 1951 5 Sheets-Sheet2 INVENTOR. RAY C. R F'EIN Ewes. BY

IIIIII H I' K IIII Un -l. ATTDRNEVS.

Oct. 7, 1952 R. c. RIFENBURG 2 612,672

APPARATUS FOR FORMING AND LINING PIPES Filed May 31, 1951 5 Sheets-Sheet3 88 ENTOR,

RAY C. RIF'EN BURG A Ens.

1952 R. c. RIFENBURG 7 APPARATUS FOR FORMING AND LINING PIPES Filed May31, 1951 s Sheets-Sheet 4 INVENTOR.

RAY C. R F'EN BURQ A TTO/TNEKS.

Oct. 7, 1952 R. c. RIFENBURG 2,612,672

APPARATUS FOR FORMING AND LINING PIPES Filed May 51, 1951 5 Sheets-Sheet5 IN V EN TOR.

A TTOKNEI S.

RAY C.RIF'ENBUEG.

Patented Oct. 7, 1952 UNITED. PATENT OFFICE v AI PARA TUS roizggigigfrucso e it 7 Ray- C. Rifenburg,-B1-ooklyn, N. Y.,' assignor to.

ConsolidatedEdison Company of, New York, lnczsNewiYork, -,-N: Y., acorporation-of: New

York

' ApplicatiomMay s1; 1951i Serial -N0. 229,137"

V 17' Glaims;

This invention relates to cond-uit-'forn'i-irig 'apparatuswherein-conduits are shaped trom plastic material, such asconcreteandthe like The invention relates-more particularly to means forapplying a lining material to the interior surfaces of such conduitduringthe:operationof the conduit-forming apparatus whereby--such-esurfaces may be made smooth.

A conduit formed of initially plastic l material, such-as concreteandthe 1ike,-is employed on a large scalefor containing, fo'r exampleelectrieal cable,- and; of course-,- I 'for conducting fluid; theconduit usually -beinginstalled underground. Such conduit usually 'is lformedby pouring concrete into a vertical mold, there beingatthe bottomof such mold" a suitable-mandrel which is rotated and simultaneeuslymoved longitudinally upwardly through the mold The mandrel,incombi-nationwith; for example; a spiral-worm and spreader palms; I 4wh-i'chare movable therew-ith, serves to press-the-plas'tic' materialagainst the inner surfacesof the formas they rotate and rise, therebyforming a hollow shellor pipe section. The---in-terior walls of 'suchconduihns formed in this w-ay tend tdibe' rough and somewhat pitted sothat it is diflicul-t to" draw there- 7 upon being rotatedand raised toshape the con-v through, for --example,-- electrical cab'les'andthe likewithout damage-to the Cab-1B5? If the conduit is -for fluid? the'flowthereof- :may be retarded by such roughness. Hence i-t-is-th'e---present'-praotice to attempt-to eliminate such roughne'ss by;for-examp1e,- wire-brushing the insides :of such conduit.- But this -hasbeen found to be'expensive and-notaltogethersatisfactory. r One of theobjects of-the-present invention-is to overcome the abovedifficulties-pr -=to* reduce same-to insignificance.

The invention -i-n one aspect thereofl 'is con!v stituted by -a paireof-mandre'ls :toriuse with a con-.-

duit mo1d,:which;'mandrels are'mounted incoaxial relationship. for;movement axially relative to. one another within. preselected .li-n'iitsu and=-a1smare mounted for rotational and longitudinal-movement relativeto the mold. Means'are provided for, supplying. a conduitliner fluid,forg'example, cement .mixed with. water, to -,an. orifice. which opensupon a region, between such .mandrels, the opening andclosing of such'orificcjbein .eficted by moving themandrels' away or toward one an-'other, that is, .the orificeis controlled 'in response to the. positionof. one mandrel relative to the other. The-conduit'mold customarilyisirr a ver'--' tical position, the mandrels initially being positionedat the bottom region of--"the. moldwhen concrete is poured thereupon,the mandre1s there duit by pressing the plasticmaterial against-theinner sides of the mold. The. conduit :liner. Ifluid isdistributa'bleuniformly. to all parts .of anexit. port formed *betweenxsaid mandrelssuchiport coming into existencein response .tozthe separation of. suchmandrels; One of: themandrels'acts to smooth the vconduit liner fluiduniformly againstthe inner surface of theconduit asit is formed,= such Iinner surface .ibecoming, relativelyvery smooth and -of much lowercoefficient-of -fric-. tionandthusless abrasive as compared with innersurfacesin conduits formed in apparatus of: the character heretoforesuggestech: .The man-. drels preferably are drivablyxassociated with ashaftby which theymay be rotated. and longi-; tudinally moved relativeto. the mold. Suchshaft may.- be provided withapassage through which iprovided for controlling the flowof: liner fluid to the imandrels inresponse i to preselected positions ofsaidmandrelslongitudinally-ofwthemold. f Various, further and more-specificobjects,- features and advantages of the inventionwillclearly-appear. from the. detailed description given -belo-w --taken in connection with the accompanying drawings which: form :a part' ofthespecification and illustrate, by way-of'exampl'e, preferredarrangements of 1 apparatus for carry-' ingout the invention.- Theinvention consistsiin such novel combinations of features as may beshow-hand described-in connectionwith the apparatus-hereinxiisclosem- 1I i In the'dr'awi-ngs: Fig-.- 1 is a sideview, partly in sectionandwith' parts broken away, showing one embodiment ofthelpresentinventionp I Fig: 2 :is a schematic diagram or one-form ofthe-invention including. the parts shown inFigl l and also illustratingone form of wiring diagram for. 'operatively associating:various=e1ement5ioi this form: of the invention,- and s also showingmeans. fortcontrolling the; flow QOf-fillidifilt) this formofzapparatuspFig. 3. is :a sectional? view. taken substantially alongline 3+3ofFig'.2;H I Fig.4 is: a detailedside View,..par.t1y: in sectionand-.iwith :parts' :brokenkawaurof tan'lcymeams'aem-r .p'lo'yed' in the:present:-invention;;1

.a bore mandrel Ill and a trowel mandrel are associated in a novelmanner to appear herebelow. Such mandrels are herein designated as H.These mandrels are drivably associated with a shaft member 12 in anysuitable manner and in the form shown such shaft is firmly secured tothe bore mandrel H) centrally and coaxially thereof by a threadedengagement therebetween as at [3. The shaft 12 and bore mandrel [8 maybe locked in such threaded engagement by any conventional means for thispurpose.

The mandrels H] and l l preferably are of metal construction and are ofgenerally cylindrical conformation, the surfaces thereof whichact uponthe inner surfaces of the conduit preferably be ing cylindrical althoughit is possible for other suitable surfaces of revolution to be employed.The shaft I2 is provided with a longitudinal passage l2a therethroughfor the purpose of conducting the conduit linerliquid to the man- 7drels as will appear more fully herebelow.

The bore mandrel ID is provided with an outer end face, as at Illa, andan inner end face as at I01), and also with a passage therethrough asatI having an orifice id in face- Nib. The trowel mandrel ll is preferablyof slightly less diameter than the bore mandrel l6 and is also providedwith an outer end face I la and an inner face llb. The latter face isshaped for conforming to the inner end face Illb of the bore mandrel l0whereby orifice Hld is closable in responseto the movement of the faceslllb and Ilb into engagement. A replaceable sleeve We may be shrunk uponand form part of the mandrel Ill.

The trowel mandrel ll may be drivably associated with said shaft 12 viasaid bore mandrel ID, that is, the trowel mandrel may be mounted uponthe bore mandrel [0 for angular and axial movement therewith. The meansfor so-mounting such mandrels is constituted, for example, by an openspider [3a, which supports a resilient member or spring I4 which, forexample, may be in the form of a flat U and which, viaan interconnectingbolt l5, exerts a thrust upon the trowel mandrel II which urges saidmandrels together, that is, urges the inner end faces lab, llb towardsone another. The interconnecting bolt I5 is provided with a head [5a anda nut Nib, the latter element engaging a suitable threaded portion atthe outer extremity thereof and also engaging the outer end face Ila ofthe'mandrel II. The nut I51) may be turned to a desired position foradjusting the tension upon the spring I4. Said bolt preferably has apassage therethrough at I50 for a purpose to appear herein after.

The above-mentioned spring and bolt structure I4, [5 interconnects themandrels for axial movement together, and also adapts .them for movementaway or towards one another within preselected limits. Suitable meansare provided for insuring that they also rotate together comprising aplurality of dowels, as atlB' and I7, which are rigidly secured to oneof the mandrels, for example, II, and which engage loosely. withinformed .under pressure adequate to overcome the spring I4 thereby toseparate such faces and to open the port l8. Such port comes'intoexistence, in the form shown, only upon separation of the end faceslfib,Ill). The spring It may be capable of closing the port 18 when thepressure of the liner liquid is reduced, for example, to atmospheric.However, under'some circumstances it is desirable to accelerate theclosing of the port it, that is, the closing of the faces 10?), llb bysupplementary means as when a very viscous liner liquid is employed.Such means are constituted by an electromagnet, as at l9, which may beannular in conformation and which, in the form shown, fits into acorresponding annular recess formed inand concentric with the mandrelII. In order to cover such recess, an annular brass plate 20 isprovided, the upper surface thereof (Fig. 1 being flush with andcomprising a part of the inner end face Ilb.

The mandrels l0 and H may be employed with advantage in the so-calledvertical mold method for forming a conduit from plastic material, suchas concrete, and such a vertical mold is shown in Fig. 1 at 2|, whichmold is cylindrical in shape with a circular cross-section. The moldcross-section may be polygonal, for example, square. A well member 22 ismounted at the bottom of the mold 21, such well member having outerdimensions preferably the same as the inner dimensions of the mold 21whereby it can be secured to such mold in the area indicated generallyat 23. The upper portion of well member 22 is provided with a flange asat 24 which,

in cooperation with the mold 2|, will form a suitable joint portion 25in the conduit. Such conduit is indicated generally in Fig. l at 25.

The well member 22 provides a housing for the mandrels I0 and llfwhenthey are in their lowermost. position, as viewed in Fig. 1, and-suchwell member is provided with a mandrel seat in the form of an inturnedannular lip, as at 22a, for thepurpose of providing a support for themandrel H and in turn mandrel I!) when they are in their lowermostpositions. In order to assist in aligning these'mandrels as accuratelyas possible at the outset of their longitudinal and upward movementthrough the mold 2|, the well member 22 may be provided with inner borediameters which are only slightly larger than the diameters of the boremandrel In and the trowel mandrel II. That is, such inner bore diametersof the well member 22 are slightly in excess of the diameters of thecorresponding mandrels in order to permit free axial movement thereof.

The' inwardly extending annular lip 22a. defines'an opening in thebottom of the well mem-' ber, as indicated at 22b, which permits anopera tive interconnection between the mandrels l0, H, and the switch21' "which is employed as an element in the means for controlling thepressure of the conduit linerliquid. The switch 21 isnormally open.However, when themandrels are in the position show n in Fig. l, theswitch is urged to a closed positionthrough the intersmears plasticmaterial is poured.- The cap member at which ls seeured 29 may beshaped, as shown, to form, in com bination with the bore mandrel, ajoint portion 3B in the conduit 26. I

As-above mentioned, it is the normal practice in apparatus of thiskind-to hold the mold '21 ina-vertical position and-to pour the plasticmaterial, such'as concrete, in at the top through opening 129a, andthereupon to rotate and raise the -conc'luit 'shaped mandrel. In orderinitially to assist in pressing the-concrete so pouredinto themold'against the interior surface thereof the following may be employed:(a) a primary head 3la having large helical threads-formed in-"the sidesurface thereof; and (b') a plurality ofspreader palms as are wellillustrated in Figs.

6 and '7 at 3| and 32. Such spreader palms preferably are rigidlysecured to the rotatable shaft l2 by means of a collar 34 which mayembrace said shaft and may be keyed thereto as bykey 35.

Also shown in Fig. 3 is a commonly used form 'of mold 2|, the latterbeing divided into halves 2la; 211) which "are hinged, as at 21c,thereby permitting an easy opening of'the. halves afterthe formation ofthe conduit. Such halves 2 la, 2 lb also may be provided withlongitudinally extending end flanges 2ldand 21c at a point preferablyopposite .to the" hinge I whereby the mold halves may be securedtogether by any'suitable fastening means. A mold havingtheabove-mentioned square cross-section isiindicated inbroken-lines at 2|(Figs. 3 and 7).

It will .be seen that the-primary head 31a and the spreader palms3l-'-33, beingmounted' above the bore mandrel l0,will initially act uponthe plastic materialan'd by centrifugal force will press same outwardlytoward the inner surfaceof the mold 2|, thereby preparing gsuch surfacefor the bore mandrel l0.

Referring now-to Fig. '2, it will-be seen that the mandrels l0 and IIare here shown .near their lowermost position but slightly raised abovetheir position, as shown in Fig. l. a

As above mentioned, thehollow shaft [2 is 6" means, is connected to theshaft 12; for example, through a swivel joint indicated generally ait 44(Fig. 2) which will communicate axial thrust to the shaft l2 from therack -a'nd pinion-l0 and still permit said shaft to rotate undertheinfluence of themotor 38. Suchswivel joint ,maybe provided with suitablethrust bearings for'communicating such: thrust 'of 'th'e-ra'c ariapinion mechanism and, as -:-wn1 be described connection with themeans-for dir'ecti-iig-condi-ii t liner liquid to the mandrels, theswivel jointmay also be employed as a device-for connectin a flexibleconduit to the rotating shaft 12 thereby to conduct sushi-mum to thepassage 121 in the shaft while the la-tt'e'r is rotating. Sui-tab1emeans '(not-siiown) may' be employed "f restraining such swivel joi-ntfrom rotation thereby preyenting- 'twisti-ngof such flexible bonduitfiAs shown in Fig. '2, the 'plastic materialsuch as concrete may bepoured-in 'small increments into-the mold 2l. upper-surface; i by abroken line atl'5, -isf-ormed by-one of such increments, such'ma'ter'ialbeing shap'ed to formthe conduit '26 by the pnmarynad, spreader palmsand 'mandrels in amanner which will be i more fullydescribedhereinafter.

The-conduit liner: liquid, as a'bove mentioned, is directed to themandrels-llll ll under pressure (see Fig. 1). The'port l ais pename, aform shown, under the; influence of 'siich liquid pressure, wherebytheliquid agma-access to the irinergsurfac'es of the'condu'i t in a uniformand highly advantageous manner lay-virtue o'f theannular conformation ofthe port l8;

It has been found desirable to force's'aid port is open, that is',;toseparate 'such inner em rates, under the influence of suchliquid-pressureat the outset of the conduit forining operation aiid toarrest the flow of such liquidbyremovi-rigsuch pressure upon the linerliquid atthe'termi'riation of the conduit-formingoperation whereby theresilient means' l 4 can-urge s-uchinner end faces into' reen'gagementtherebytoclose-thepor't 18. Such closing, as above" mentioned; may be easistedbythe action of the electromagnet-"I'B if desired, It is desirableto provide r quick; dissipation of the pressure upon such fc'o'iiduitliner liquid when-the port l'8-re'aehes'c t'he mounted for rotationalmovement and also for movement longitudinallyof'the mold 2! whereby saidmandrels are raised upwardly through the plastic material in the moldthereby to form the conduit. As schematically indicated in Fig.

2', the shaft 12 is rotatable by means of a pair.

of bevel-gears as at 36 and 31, the latter'being operatively connectedto a torque source, such as electric motor 38, for driving said gears.The bevel gear 36 may be held axially stationary relative to the mold 2|by suitable means (not shown) and may surround the shaft 12 and be keyedthereto, as by a key 39, whereby torque is communicated to the shaft 'bythe motor 38 causing said shaft to rotate and at the same timepermitting it to be raised or lowered'relative-to the mold 2i.

The means for. raising the shaft l2, that is, the ,means for shiftingsame longitudinally through the mold 2'I,, may consist, for example, ofa rack and pinion device indicated generally at 40 and comprising a rack4| and a pinion 42, the latter being d'rivably associated with a torquesource, as at 43, also comprising an electric'motor; The rack 4|, by anysuitable to accomplish such quick pressure dissipation, that two tanksfor the liquid should-be employed, including amaster tank indicated atGB and'an intermediatetank at 4 (Fig.2). Thelatter'tank is of re1ativelysmall volumeeoin'pared to -the former andsis of such volume that it ispossible,

Jupon'opening of an exhaust valve to theatmo's' phere; for the pressuretherein quickly'to be' reduced toatmospheric; Thus. a disadvantageousdelay in the reduction of conduit liner liquid pressure is avoided whichmight otherwise occur if an effort were made to'dissipa'te suchpres'surein a relatively large tank,"as at 46.

The conduit liner liquid can consist of any suitab1e substance which,when smoothed-againstthe interior of the conduit while in the process offormation, will smooththe inner surface'ofthe conduit, make a permanentbond therewith and thereby reduce the coefficient of friction of suchsurface and make it" relatively low abrasive qualities. I have found itadvantageous te -employ, for example, any one of the following:

(a) So-c'alled neat cement comprising. a mixture of cement with water;

- -(b) Grout which"comprises amixtureofiiine sand with cement and water;and l 1(0) Amixturewith either ,(a) or (b) of finely ground soapstone g,The liner tanka i] isconnected to the shaft I2 .via aconduitindicatedschematically-in Fig. 2 at 48 via said swivel joint 44;The conduit 48 is fiexible-inorderthat it mayifollow the movements ofthe shaft- I2 as itshifts. longitudinally. A

twisting of theconduit 48 is avoided b y virtue of the;,swivel jointmeans above described; Ifdee Sired a-valve, as atq9, is interposed intheconduit 48 s J v w The conduit liner liquid is forced fromithe tank41;,to the shaft I2 and hence to the mandrels I G, I I under theinfluence of fluid'pressure in tank 47; for example, air under pressure,such gair being conducted to: the upper portion within the. tank sureThe selector valve 5i is provided with shuttle valve members 52 and 53which-are rigidly secured to a valve shaft ,54 and which are axiallyshiftablewithin a valve body 55. In the position of theshu'ttle members52, 53, as shownin Fig-m2, the latter, shuttle member elo sesnthecon:duit 5D thereby; preventing the :appli cation of pneumatic pressure uponthe liguid in the'tank 41 and opening such tank tor-atmospheric pressureviaanexhaust conduit 56:. By means of a T-joint 51, and aconduit-58, theconduitifl, at thelocation between t'ank 'land valve 5 I, is connectabletofihe exhaust conduit 56 as shown in Fig. 2.

A reducing valve59 is provided in the conduit 5llat a-point intermediatethe selector valve SI and a conduit 56 which interconnectslthe conduit50 to the master or larger tank 46. Thus'a higher pneumatic pressure isexerted upon theliquid in the tank 46 ascom-pared to that in tank 41.The purpose; of such a reducing valve is to permit liquid from thelarger tank 46 toflow into the On extrem f sol o d-1. 2 e nn tedto theother extremity of suchsolenoid being-connectedto theother side L2 bymeans o f-. a lea d Glextending toaterminal S il of said switch 64 andbya lead 69 which interconnects; another terminal l li of such switch ,64,tosaid power line The solenoid 1G5 controlling the switch- 64 isunderthe influence of the above-mentioned switch IZ'Lwhich is normallyop'en, but which is closable in response tc the mandrel ,It being seatedin its lowermost position as-shown in Eig, 1. Thecircuit in which thesolenoid 6 5 is connected comprises said lead 69,.a lead II whichinterconnects the terminal It! with a ter ninal I2 oftheswitch 27, alead l3 which-interconnects the power line L1 to anoth er terminal 74 ofsaid switch 21. f f n j 1 The switch 6d, in 'a'ddition to beingfoperableby the solenoid 65, is also operable response to said mandrels reachinga position ator near the upper extremity of their travel, as viewed inFig. 2, through the/intermediary of a co1lar 'I5 which is rigidlysecured to the'shaft I2. Theclos ing of the switch Why such collar will.energize.

the solenoid 62 thereby actuating the selector valve to remove thepneumatic pressure upon the liduid'in'tank 41., and to place suchliduidunder atmospheric pressurel. 'jSuch collar 15 ;isfwell'i1- lustrated inFig l and ,is' constituted by fanouter electrically conductingfrhetal.po'rtioifv 15a and an I inner portion i521.which'fllelectrically insulates for holding the arm'td same from theshaft}? for'al'purpose to'be ap-t parenthereinafter;

f Thes'w'i't ch 64 is closable by upward movement of the c'ollar 'l5through the intermediary are resilient arm, 540; which is pivotallyassociated with such switch whereby the'collar raj-can engage suchwarm,urge thejswitchtoa.closed conamen and, by ,distortin-g fthe resilientarm; move therepast and leavethe'f'switch in a. closed cont n. Suitableresilient ndea l ls l are. employed in" a preselected i' lti'tude {5whereby suchengagerelative to the swi-tc inent .forv closingo the switchcan occur in re smaller tank 41 at the'same time as the exertion of adesiredpneumatic pressure upon the liquid inthetankfl. r

The pressure regulating valve SI n ay be pro vided in the conduit 55 ata point between the source of air pressure andthe conduit Bil. I

- The selector valve 5|, as above explained, is

controlled in accordance with the position of the connected with theshuttlevalve'members 52, 53

of the selector valve 5L When the solenoid .62 is energized, the shuttlevalve members 52,-53 are moved to the position shown in Fig. 2wherespouse to iipward mov ment of the collafrl I But upon return or'downward r'n'overnen t(ft-suchcol- 1211 the arm fi lcwill "rinit thepassage' of such collar without ope' ftheswith' :64, that is, the 'arni64a can' t closure of po'rt I8. a

i In orderto assist; the spring fifil closinglthe I port, IBsvhenthe inanfdrelsTreach a' preselected longitudinal position at, or near, theuppermost as when such solenoid is ,deenergized such shuttle valvemembers will fall to their lowermost positionwherein the exhaustconduit-56 is closed-and pneumatic pressure is exerted upon the tankd'l, the air under pressure passing between the shut.- -tle valvemembers 52, 53. The solenoid 62 in turn is under the influence of aswitch lidfthe latter being under the control of asolenoid ,65, and acollar I5. v-

position thereof, the'felectronia'gnet I9v is energized in response tothe closing-of saidswitch 64 by the collar 75. This is accomplished bymeans of an electrical lead 76 (Figsfl, and 2,), which: is connected atits upper'eXt-re'mityto the portion 15a ofthe collar 15 and at its lowerextremity to the .electromagnet: it, iQSaid 1 electrical lead 16preferably extends through a passage. I 50 formed in the bolt I5LAsschematically indicated in Fig.2, said lead l5=is connected to oneextremity otthe electromagnet I9, the other extremity fof N i angularabout a pivot, to permit suc d 'nward passage or the col-.

aeiaem .9 such. electromagnet being grounded as;-at 11-. Thus when thecollar 15 closes said switch 64, an

electric circuit is: completed during the period of engagementof collar.15 and arm 64a, such circuit comprising the lead 69, arm 64- and 64a,collar 15, lead 16-, coil. l 9 and thence from the ground at 11 throughthe shaft l2 and the-grounded frameworkof the machine to the groundedlead 13a and thence to the lead 13. I I

The means for controlling the level of conduit liner liquid in the tank4'! will now be described, reference being had to Fig. 2 wherein themaster liner tank 46 is connected preferably near the bottom thereof toa point near the bottom of the tank 41 by means of aconduit 18. Thelatter has normally closed valve 19 therein under the influence of asolenoid 80. As above mentioned, air pressure atall times is exerteduponthe upper surface, as at 46a, of. the liquid in the tank 46. A lower airpressure is exerted uponthe upper surface, as at, 41a, of the liquidinthe tank 41, suchpressurebeing lower by virtue of the reduce ing valve59 above mentioned. When the solenoid 80 is energized, the normallyclosed valve 19 is opened.therebypermitting .liner liquid ,to flow fromtank 451into tank 41. The valve lfl, via said solenoid 80, is controlledby the depth of the 1-6 and topass. through a centrally located bore inthe contact 85. .The cup 89 is rigidly secured. to the. upper innersurface of the-tank l1.

-.It.hasbeen found: desirable. to. provide .a sobetween the conduit: 59and. the-liquid. surfacein-the tank.v 4 1 The-purpose oflthefillercollar isto keep-the volume: oi pressure fluidto a minimum in ordenmoreuquickly to reduce the pressurev once the valve-54 initank il: is:opened to the atmosphere.

. In operation the.mandrels. 1 0 1 and. I [1' are. initially movedtotheir lowermostpositionwith. the

mandrel ll- 3 seated; against. theseat. 2211 and the inner endfa'ces1012;. Idle-in. engagement-whereby the orifice Illd, and hencethe port[-8 are closed.

v When the .mandrelwl Li s: so seated; the normally liquidv in the tank41 by the following means: i

leads,'suchas 82, which are under the influence of a device responsiveto the. depth. of the liquid in tank 41. Such switching means areillustrated in detail in Fig. 4 and. are constituted by a switch contact84 and another switchtconta'ct 85. The former is constituted by amagnetized member which attracts to itself the contact 85, the latterbeing in the form of a collar loosely embracing a shaft 86 of insulatingmaterial, such as laminated phenolic. When said contact members 84-. 85are in engagemenhthe solenoid is energized thereby opening the" valve19'. Means are provided for "separating said contact members in responseto theliquid in tank 41 reaching a pre selected'high level, such meanscomprising a float 81 to which is secured the shaft 86. Saidcontact 84is rigidly secured to the upper extremity of the shaft 86 whereas thecontact 85 is axially shiftable along said shaft when not held againstthe magnetized contact 84. The contact 85, as shown in'Fig. 4, isshiftable between an upperextreme positionshown in solid lines and alower extreme position shown in broken lines. In the latter positionsuch contact 85 is supported by means of'an open spider 88 similar inshape to open spider l3a. When the tank 41 is empty or the liquidtherein reaches a preselected low level, the float 81 will be depressedsufficiently to allow magnetized' contact 84 to attract and engage thecontact 85. When the liquid level in tank 41- rises to a preselectedpoint, as at 41b, the contacts;

.85 will be separated by means of a cup member 89 of'insulati'ngmaterial by virtue of the smaller diameter of the contact 84' which iscapable of movement to the inner surface of the cupwhereasthe'larger'contact 85' will engage the cup-lip. and be restrained fromfollowing the contactt-l whereupon contact 85 will be removed from themagnetic influence of thecontact 84', and will drop to the lowermostposition shown in broken lines (Fig. 4).

It is desirable for the'shaft-BG tobe centrally attached to the float 81and to-the contact ,84

open switch. 21. .is, closedby means.- of the annular member- 2 8(;Eig.;1-) thereby completing. the circuit of the... solenoid 65,energizing same. and opening the switch..i k assuming, the latter.inftially to be closed-.- I he openingof the, switch Ellbreaks thecircuit-.of-the. solenoid 68 thereby causing the shuttlavailre members52,; 53- to .drop from the position shownain Fig- 2 totheir lowermostposition thereby closing the conduit '56 which theretofore was-:incommunicationwwith tank. 41- and. .o pening: conduit to the passage ofair,under-pressurevto the tank. 41 Suchpneuniatic. pressure=may,-.-forexamp1e,. be about 20 p us. i. .upon the,liquidklevelsLid-whereupon the liquid. .isforced: from: the tank 4.1- tothe orifice Hid.- via the, conduit.- 4'8;.,-the shaft I2 and.- passageInc. Theelectromagnet. 1-9; atthis time. is deenergized. and. .portl8ris held-f closed by the. spring I 4. andalso. bye-the, force-. of;gravity acting upon thebcre mandrel .-l [land-the shaft l2.Theplasticmaterial, suchas. concrete, may-now bepoured into the moldvzlata-pre-selected rate, and the mandrelsv I arethen rotated. and raised.by energizing. the motors..38{ and. 43-. It. hasbeen found desirable. torotatettheshaft. I2 and hence the primary. head spreader palms-and:mandrels at approximately 300R. P.;M. When the trowel mandrel Llhas-been:lifted- 011 of the seat 22:1,.as

shown .in..2,- the" action. ofthe liner liquid under. pressureincombinationwith the action of gravity., ppon thelower-mandrel; H',exerts sufficientforcestoovercome :thespring M therebyte separate. the.inner end faces Mb; I lb" and thus to open the-port l8. Thespreaderpalms 3 I, 32 (Figsufiand 7') acting in combination with theprimary head 31a; initially throw the plastic material against the innerinterior surfaces of. the mold and the bore mandrel HI thereafterpresses- .same thereagainst.

The port l8-.-b'eing open,..the conduit liner liqu'idvis uniformlydissure above the liquid lever-41a is"released and the pressure issubstantiallyinstantaneously reduced to atmospheric by virtue oftherelatively smallvolume between the level" of the liquid in such'tankand the orifice'of conduit'Sll. Coincident with-thereduct'ion ofpressure of the liner fluid, the electromagne't I9 is momentarilyenergized hy'virtue of the collar 'lE engaging said 'arm- Bid, andbymeans of the aforementioned circuitfsaid electromagnet thereby assistingin pibmpny, closing .the' port 1 I 8% The mandrels i and Hmusthelifte'dentirelyput of the mold 2l jand consequently the shaft I 2is urged upwardly'after the collar 15 engages the "arm 64a. As abateexplained, saidarm is'of resilient construction and bends to permit thepassage of the collar 15 and 'thereu'pon is disconnected-therefromwhereby fthe electromagnet I9 is deener gijzed' 'Conseeuently theelectromagnet is ener- 'gized'. only during the period of engagement ofsaid f collar i5 and arm 64a."

While the invention has" been" described with I respectfto a preferredexample which will give satisfactory-results, it will be understood bythose'skilledin the'art after understanding the invention that variouschanges and modifications maybem'ade without departingfrom the spiritand"'sope of thefinventiomrand: it is intended therefore in theappendedclaims' to coverrall such ch nges and modifications. v

'wh'at isclaimed as newand is desired to -"be securedby'LettersPatentisfl. Foruse with a mold in a"conduitforming a paratus, a pair of mandrels;means for mounti'ng said mandrels :for movement between arelative-position wherein they are in engagement and another relativepos'ition whereinpthey are separated by apreselec ited distance; one ofsaid mandrels having a pasjsagetherein with an ori fice' positioned forbeing closedwh'en'said mandrel's' "are in engagement; and means forsupplying a fluid material to such passage, such material having egressto 'the-conduit in response to'the separation of said mandrels. j V

.' For use with a mold in conduit-forming apparatus, apair ofmandrelsfmounted for move ment relative to'one another withinpreselected limits s'aid' mandrels} having inner end faces shaped forengagement, a; port formed between said' mandrelsbein'g' closableinresponse to engagementjof such faces Fahd operable in response to theseparation of such faces, said-mandrels being mounted for m'ovementlongitudinally of and'rotation inth'e-m'old, and means for directingaliquid 120* a region' between said mandrels, su'c'h li'quidhaving egressthrough such port in response to -the opening of the latter.

3. ForhsQwith' a mold in conduit-forming apparatus, 'a bore mandrel; atrowel mandrel;

means for mounting said mandrels for movement relative to one another,one of said mandrels having a passage with an orifice in a face thereofwhich is closablein response to said mandrels assumin'g'a preselectedrelative position; means for mountingsaid-mandrels for rotational andlongitudinal movement relative to the'mold; and means for supplying aconduit liner material to' such' passage, such material gaining egressto thei'nner. surface of the conduit being formed in the; mold; inresponse to said mandrels moving out ofisuchpresele'cted relativeposition.

4;'Foifluse withj a mold in a conduit-formingapparatus, a'sha'ft mountedfor longitudinal and rotational movement in the mold, a bore mandrel,

5. A conduit-forming apparatus includingdn' combination: a mold, a'shaftlongitudinally and rotatably movable in said mold, a bore mandrehatrowel mandrel, said mandrels being drivably associated with said shaftformovement therewith,

said mandrels having conforming inner end faces,

said shaft having a passage therethrough in communication with an orifce in one of said end faces, such passage being closa-ble in response toengagement of said inner'end faces, and means for mounting said mandrelsfor movement toward and away from one another for controlling 6. For'use with a conduitmold in conduit forming apparatus, a pair of mandrelsmounted in coaxial relationship for movement axially relai tive tooneanother withinpreselectedlimits, said mandrels having inner endfaces, one of said mandrels having a passagetherem with an orifice atits respective inner end face, a passage of fluid through such orificebeing controllable in response to the axial positions of said mandrelsrelative to one another; means for rotating said mandrels andsimultaneously moving same axial ly within and relative to the conduitmold; and means for controllingthe position of said mandrels relative toone another. H

7 For use with a conduit mold in conduitforming apparatus, ;a boremandrel; a trowel mandrel mounted coaxially with said bore man: drel foraxial movement relative thereto within preselected limits, said mandrelshaving inner end faces, one of said mandrels having a passage thereinwith an orifice'atthe respective end face thereof; means for controllingthe spaced position of said man drelsirelative to one another; means forrotating said 'mandrels and simultaneously moving same axially relativeto the mold for pressing plastic material against the interior surfaceof the hold to form a conduit; and means for directing a conduit linerfluid'to the passage in one of said mandrels, such fluid, in response tothe separation of said mandrels, having a passage to'the interiorsurface of the conduit portion formed of such plastic material sopressed against the mold and being smoothable against such surface byone of said mandrels. v p I 8. Apparatus inaccordance with claim 7wherein said means for directing conduit linerfiuid ,to said mandrelsincludes a m aster fluid linertank,

an intermediate fluid liner tank of 7 smaller ca-" pacity than saidmaster tank, and means for controlling the flow of liner fluid fromsaidma'sthe mold. I

9. Apparatus according to claim 7 including means for controllingthe-flow of such conduit liner fluid in response to'the position of saidmandrels axially relative to the mold.

10. For use with a conduit mold in conduit- E3 forming apparatus, a 'p'efmandrels, one of said mandrels having a passagethereinsaid: mandrelshaving conform g6 inner endi faces; means for mountin said mandrels] foraxial movement r'elativ to::one another-within preselected 'limits f-oropenirig or closing an orifice of such passage in one of the inner endfaces, said mandrelsbeing-positionable initially at a bottom region ofthe conduit; moldrmeans for rotating said mandrels and for; moving samelongitudinally of. the'moldaforpressing plastic material against theinner sides or the mold; means for controlling the movement ofsaidrnandreljs relative -to oneanotherg and meansf for directing aconduitliner fluid to such passage in one of said mandrela -suchfluid-flowing between said mandrels in response to the separationthereof, such fluid being smoothable against the interior surface of aconduit formed of such plastic material by at least one of saidmandrels.

11. For use with a conduit mold in conduitforming apparatus, a boremandrel having an inner end face and a passage therein with an orificein such face; a trowel mandrel having an inner end face formed forconforming to said first-named inner end face; means for mounting saidmandrels in coaxial relationship for movement axially relative to oneanother within preselected limits, said inner end faces being movable toclose engagement for closing such pas sage and being separable withinsuch limits for opening same to permit the egress of fluid from betweensaid mandrels; means for controlling the position of said mandrelsrelative to one another;

and means for rotating said mandrels and simultaneously moving samelongitudinally of themold.

12. For use with a conduit mold in conduitforming apparatus, a pair ofmandrels each hav: ing conforming inner end faces, one of said mandrelshaving a passage therein with an orifice at the respective inner endface thereof, said mandrels being movable relative to one anotherwhereby such orifice can be opened or closed to control the fiow of afluid therefrom, said mandrels being movable angularly andaxaillyrelative to the mold for pressing a plastic material against theinner surfaces of the mold in response to such angular and axialmovement;

means for controlling the position of said mandrels relative to oneanother whereby the passage of fluid from such orifice is controllable;and means for directing a conduit liner fluid to such passage, at leastone of said mandrels acting to smooth such fluid against the interiorsurface of the plastic material so pressed against the inner surfaces ofthe mold.

13. For use with a conduit mold in conduitforming apparatus, a boremandrel having an inner end face and a passage therethrough having anorifice in such inner end face; a trowel mandrel having an inner endface formed for conforming to said first-named inner end face; means formounting said mandrels in coaxial relationship for movement axiallyrelative to one another within preselected limits, said inner endfacesbeing movable into close engagement for closing such orifice and beingseparable within such limits for opening such orifice to permit theegress of fluid between said mandrels; means for resiliently urging saidmandrels toward one another; means for rotating said mandrels andsimultaneously moving same axially relative to the mold; and means fordirecting a liner fluid to such passage in said bore mandrel,

14'. 'Ina apparatus of the, class described a bore I mandrelhavingainner: V and: outer-end: faces ,and a passage therethrough.extending fromvonezcnd face to.-the others; ashaftzmember secureditdsaid bore mandrel: and havingrai passage therethrough which islincommunications withcsaid first-named passagei. a: trowelfmandrellhavingiian: .inneri end face formed for: conformingtoLxsa-idtfirstenanted inner; end face of .saidZbQramandrely, saidrman-zdrelsbeingcin the shape of'solidsofrevoliitionpthe diameter oftsaidtrowels; mandrelrbeing'smalIer thanthat of said. b'oreimandrel; meansfor mounte ingsaid mandrelscimcoaxiat relation for moves-1 ment; axiallyrelative toz-one another; within pre: selected limits, such inner: endfaces? of said man,- drels; being movable 1111302 01058! engagementeforclosing the: orifice :of' thepassagei thezinner end face of said boremandrel, said inner end faces being separable within such limits foropensaid mold against the sides of the latter to form a conduit inresponse to such rotation and relative axial movement of said mandrels;and means for directing a conduit liner fluid to said mandrels via saidshaft, such fluid having egress between said mandrels in response toseparation of the latter, said trowel mandrel smoothing such fluidagainst the material so pressed against the sides of said mold by saidbore mandrel.

15. In apparatus of the class described, a bore mandrel of cylindricalconformation having inner and outer faces and a passage therethroughextending from one end face to the other; a rigid shaft member securedto said bore mandrel at-the outer end face thereof and having a passagetherethrough in communication with said first-named passage; a trowelmandrel also of cylindrical conformation and having an inner named innerend face, said trowel mandrel being of smaller diameter than that ofsaid bore mandrel; means for mounting said mandrels in coaxial relationfor movement axially relative to one another within preselected limits,said inner end faces of said mandrels being movable into closeengagement for closing the passage in said bore mandrel and beingseparable within such limits for opening such passage to permit the fiowof fluid therefrom to the periphery of said trowel mandrel; acylindrical mold; means for moving said mandrels axially relative tosaid mold; and means for simultaneously revolving said mandrels.

for mounting said mandrels in coaxial relationship for movement relativeto one another'within preselected limits, one of said mandrels having apassage therethrough, means for resiliently urging said mandrels towarda preselected relative position in which position such passage isclosed, and means for directing a liner fluid under pressure to thepassageway in one of said mandrels.

17. In apparatus of the class described, a boreforming mandrel having apassage therethrough, a shaft member secured to said mandrel coaxiallytherewith and having a passage therethrough 16. For use with a conduitmold in conduitforming apparatus, a pair of mandrels, means incommunication with the passage intsaid manmounted upon the bore-formingmandrel coaxially therewith and having a substantially flat innerendface, the latter being movable directly adjacent to and in engagementwith the corresponding face of' said bore-forming.=mandrel, means forresiliently urging such faces of said mandrels into. engagement, aconduit form in which said mandrels are *operabla such form beingadapted to receive a plastic material through which said mandrels aremoved thereby pressing such material against said conduit form, suchpassageways in said shaft and bore: forming mandrel being adapted forconducting a conduit liner fluid, and means for moving said shaftrelative to said conduit form.

' RAY C. RIFENBURG.

REFERENCESCITED The following references'a're of record in the file ofthis patent: g I 1 UNITED STATES, PATENTS Number a Name 1 Date 907,724Boyle Dec. 29, 1908 1,838,546 Halstead Dec. 29, 1931 2,143,448 ORourkeJan; 10,.1939

